HOW TO ASSEMBLE THE GAMMA “SUPRADYNE” WITH FIVE VALVES

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HOW TO ASSEMBLE THE GAMMA “SUPRADYNE” WITH FIVE VALVES 
17.Jan.17 13:12
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Pitagora-Petru Schorsch (D)
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Pitagora-Petru Schorsch

HOW TO ASSEMBLE THE GAMMA “SUPRADYNE” WITH FIVE VALVES

        The study of the screen grid valve (§51) emphasized the advantages to be gained by its employment in the intermediate frequency stages. The present set – a very interesting achievement - puts this in practice: Although using before detection two valves with a very high gain, the size of the set is very small, due to a carefully designed screening. The circuit diagram (fig. 208) shows a common frequency-mixer-receiver employing a two-grid valve (bigrille) in the first stage:

Fig.209 shows the wiring and components on the vertical panel:

Fig. 210 shows the same on the horizontal panel:

        The set’s sensitivity reaches the upper limit, due to the employment of the two screen-grid valves as intermediate frequency amplifiers, and especially to the careful screening, allowing maximum amplification without the risk of self-oscillation. Also due to the employment of the screen grid valves, the high selectivity, common to every super-heterodyne, is here sensibly enhanced.

Following parts are needed to assembly the set:

1 "GAMMA" filter transformer.

2 "GAMMA" intermediate frequency transformers, type 1620.

1 "GAMMA" combined oscillator, 200 - 2000 m.

1 ebonite panel 36 × 23 cm.

2 slow-motion 500 cm variable capacitors.

1 rheostat 6 - 10 ohms.

1 potentiometer 400 ohms.

1 fix capacitor 3000 cm (loudspeaker).

1 resistor 3 Megohms (grid leak).

1 low frequency transformer ratio 1: 3.

Connection wire, screws, banana sockets power supply cord.

 

[The publicity section of the book contains at page 298 an advert from one of the main radio-parts supplier in Bucharest in those times: “RADIO-MATERIAL NICOLAE SARU” offering the complete set of components for the kit:]

The valves could be chosen from the following list:

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